Nokea
An atom has 2 protons, 4 neutrons, and 2 electrons. What is the approximate atomic mass of this atom?
- A. 2
- B. 4
- C. 6
- D. 8
Correct Answer: D
Rationale: The atomic mass of an atom is the sum of the protons and neutrons in its nucleus. In this case, the atom has 2 protons and 4 neutrons, totaling 6 particles in the nucleus. Therefore, the approximate atomic mass of this atom is 6, making choice C incorrect. The number of electrons does not significantly contribute to the atomic mass, as they are much lighter and located in the electron cloud surrounding the nucleus. Choices A, B, and C are incorrect as they do not reflect the correct calculation of atomic mass based on protons and neutrons only.
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What is the cellular function of cilia and flagella?
- A. Cilia and flagella are responsible for cell movement.
- B. Cilia and flagella synthesize proteins.
- C. Cilia and flagella help protect the cell from its environment.
- D. Cilia and flagella have enzymes that help with digestion.
Correct Answer: A
Rationale: The correct answer is A: Cilia and flagella are responsible for cell movement. Cilia and flagella are specialized structures found on the surface of many types of cells. They are involved in the movement of the cell itself or in moving substances around the cell. This movement helps in various functions such as propulsion, moving fluids, and sensing the environment. Choices B, C, and D are incorrect. Cilia and flagella are not involved in synthesizing proteins, protecting the cell from its environment, or aiding in digestion. Their primary function is related to cell movement and cellular transport.
Which of the following statements describes a chemical property of water?
- A. Water has a pH of 1.
- B. A water molecule contains 2 hydrogen atoms and 1 oxygen atom.
- C. A water molecule contains 2 oxygen atoms and 1 hydrogen atom.
- D. The chemical formula for water is HO.
Correct Answer: B
Rationale: The correct answer is B because a water molecule consists of two hydrogen atoms and one oxygen atom, which is a fundamental chemical property of water. The pH of water is not a property of the water molecule itself but rather a measure of its acidity or alkalinity. Choice C is incorrect as it describes a different molecule, not water. Choice D provides an incorrect chemical formula for water, which is H2O.
Which of the following characteristics is part of a person's genotype?
- A. Brown eyes that appear hazel in the sunlight
- B. The CFTR gene, which causes cystic fibrosis
- C. Black hair that grows rapidly
- D. Being a fast runner
Correct Answer: B
Rationale: The correct answer is B. A genotype refers to a person's genetic makeup, which includes specific genes like the CFTR gene responsible for cystic fibrosis. Genes are the units of heredity and are part of an individual's genotype, influencing various traits and characteristics. Choice A, brown eyes that appear hazel in the sunlight, refers to a phenotype, which is the observable characteristics resulting from the interaction of genes and the environment. Choice C, black hair that grows rapidly, also describes a phenotype rather than a genotype. Choice D, being a fast runner, is a trait influenced by a combination of genetic and environmental factors, but it does not directly relate to a specific gene in the genotype.
Which part of the cell serves as the control center for all cell activity?
- A. Nucleus
- B. Cell membrane
- C. Cytoplasm
- D. Mitochondria
Correct Answer: A
Rationale: The corrected question and answer are accurate. The correct answer is A: Nucleus. The nucleus is known as the control center of the cell as it contains the cell's genetic material (DNA) and directs all cell activities including growth, metabolism, and reproduction. The other organelles listed in the choices, while important for various cellular functions, do not serve as the central control center for overall cell activity.
In the suburban neighborhood of Northwoods, there has been a large population of deer, and residents have complained about them eating flowers and garden plants. What would be a logical explanation for the large increase in the deer population over the last two seasons?
- A. There has been an increase in the quantity of food sources in surrounding areas.
- B. The population of natural predators in Northwoods has decreased.
- C. Deer have migrated from surrounding areas.
- D. There has been a recent increase in hunting licenses sold.
Correct Answer: B
Rationale: The correct answer is B because a decrease in natural predators can lead to an increase in the deer population as there are fewer predators to control their numbers. This explanation aligns with the situation described in the question, where the deer population has increased, causing issues for residents. Choice A is incorrect because an increase in food sources would not directly explain the increase in the deer population. Choice C is incorrect as it introduces a new factor of migration which is not mentioned in the question. Choice D is incorrect as an increase in hunting licenses sold would likely have the opposite effect on the deer population.